The Turtle In The Room
by le error
Summary: Cover by neosmies /AU-Good Genes/ "If he uses my punching bag as a chew toy one more time-!" What if they learned to deal with Donatello for a while before they found a cure. Mikey is having too much fun, Raph is actually okay with everything and Leo is getting tired of Don drooling all over the sofa.
1. Chapter 1

_A/N: _This is AU from the 'Good Genes' arch. Everything is similar expect the fact that Don is less aggressive and more intelligent (a little). I got the idea from a piece of artwork on DA. It was of the Hulk hugging Spider-man gently while he was injured and the idea just sparked in my mind. Anyways, hope you like it. Review if you think I should continue if not I'll just scrap this.

He sneaked his way towards the wild assortment of pipes, crouching low and clinging with skill on the cool metal. He glared down wondering if he would be found from his simple hiding location. However, he didn't shooting himself down so easily. The darkness was his ally and he moved silently above the the rusted pipes like floorboards on ground. He shifted his weight so that he could lean on his right side, sweeping his left foot out and his hands in front of him to keep balance. Suddenly, he heard a noise after a long wait. The footsteps were loud and clumsy. Not caring where it stepped as it made its way down the narrow tunnel. He carefully craned his neck over the disarray of piles and watched the creature appear from the distance into his line of sight. It was crouched low, long snout moving just inches above the ground and sniffing.

The other swallowed hard, keeping silent and wondering if he should move away to avoid being caught. The creature's hearing was so acute it was ridiculous and to be honest he was sure that he was cheating now. The creature made a small deep moan of interest as he picked up on the familiar scent.

Suddenly, the creature stood on two legs and the other gasped. He had forgotten how tall the creature actually was. He tested his position as he moved ever so lightly towards the next pipe behind him. He clung to the pipe underneath him and turned to face the endless assortment of red looking pipes. Maybe he could reac-

"Ahhh!"

The creature grabbed hold of him unexpectedly and dropped him roughly to the ground into the sewage water where it stood. It took a moment to process everything considering it was so sudden and quick. He hadn't expected to be found by his brother so quickly.

"Come on," Michelangelo rubbed his bottom as he stood from the disgusting water and onto solid ground, "You totally cheated, Donnie!"

The creature merely stared at the small turtle with neutral eyes. Donatello lowered himself onto all fours but his hind legs were bent still and his bottom moved back and forth. Mikey chuckled, realizing that his large brother wanted to play again.

"I'm kinda hungry right now, how about we play later and get something to eat first?" Mikey asked the much larger mutated terrapin. Donatello stopped to look up at his brother and tilt his head as if confused of what his brother had said. "Eat! Yum yums!" Mikey explained further to his once genius brother. Donatello was limited on communication but he did understand somethings. Donatello seemed to throw this idea back and forth in his mind before letting out a large puff of air through his nostrils. Mikey smiled at his brother with a worried stare.

"C'mon, big bro! I'll make you an awesome sandwich and I'll put in extra ham just the way you like it." Donatello stood on his two feet once more and moved his short tail back and forth slowly. Mikey took the silence as a yes and also taking into account that his brother wasn't growling and roaring at him angrily..yeah it was a good thing. Mikey watched his brother for a while before hastily running in front of him to do a front flip then beckoned for the other to follow. Donatello followed quietly despite his heavy breathes and loud stomping.

As soon as the two arrived back at the lair, Mikey was bombarded with questions by the oldest.

"Where did you go! How could you be so..so stupid! You can't just drag him out like that!" Leo fumed angrily at the youngest.

"We were just playing a game!" Mikey countered, "Donnie likes playing hide and seek."

Leonardo pressed two fingers between his eyes and sighed deeply trying to calm himself. The youngest just didn't understand but he couldn't really blame him. Leo looked behind Mikey though he really didn't have to. Donatello was laying on the ground with his arms tucked in and his head resting on top of them. His menacing red eyes were narrowed showing signs of drowsiness from their play time. Leo felt a little relieved that he didn't have to watch over the larger sibling and turned his attention back to Mikey.

"Mikey, I know you're trying to help Don but right now he needs to stay here."

"The poor guy just needs to stretch his legs!" Mikey argued, "He's not some animal, Leo, he's our brother!"

"I get it," Leo spat back impatiently, he turned back to Donatello who was now sleeping peacefully near his once work station. "However, you need to understand that Don is..well he's really unpredictable right now."

"We've been through his, Leo," Mikey groaned and moved past his brother towards the kitchen, "He isn't going to hurt us! He knows us, I know and he knows, ya know?"

Leo felt his eye lid twitch. He fell silent finding no use arguing with his brother any longer and sighed. He really wanted to believe his carefree sibling but he just couldn't. Every time he looked at his mutated brother he couldn't find the familiar care that he once had with Donatello. His brother was gone and replaced with this..monster. He hated to think it but there was no other way of putting it lightly for him. Leo was sure that the creature- his brother could feel it too. It might explain why his once sibling was so distant from him compared to the others.

Leo remembered when his once brother almost hurt Master Splinter by a furious swipe of his enormous claw. Without really thinking Leo stabbed Donnie's large arm in retaliation much to everyone's horror. He hated how easily he had made that decision but he didn't regret it. Don could have killed their father with one hit from his claws. Don didn't know his own strength in this form but everyone was putting in their time and patient to help him. Leo could still see the scar that he had left on his brother.

"Awww did he fall asleep? How cute!" Mikey cooed dumbly as he emerged from the kitchen with a large sandwich in hand. Leo watched on alert as his brother knelt besides the sleeping beast and stroked the top of his head. Leo's heart stopped when Don opened his eyes at the touch but remained still. He seemed to be enjoying Mikey's loving affection towards him. Leo could have sworn he heard the creature purr. Donatello's eyes narrowed once more before shutting and exhaling deeply in relaxation.

Mikey took a bite out of the sandwich, chewing hungrily with gusto. Leo returned to the living room at least close enough to his brothers just to safe as always. Mikey ignored him as always. Biting into his sandwich again as he scooted closer to his mutated brother and turned on his bottom to lean back and rest his shell against Donatello's massive form.


	2. Chapter 2

Hygiene was important and even though they lived in a sewer of all places they were relatively clean. They took showers in the morning and brushed their teeth. When they were little Master Splinter would scrub their shells with a worn out toothbrush to clean them. Now they reluctantly rely on another to get the hard to reach places but the boys thought of it too embarrassing to tell any other soul.

They knew better to track mud or dirt into the lair. A lesson they learned the hard way from their father when they were just children.

So it was always a basic rule to never track any sort of dirt or grim into their home. It was rule they've all knew by heart without even thinking. However, it slipped over their heads when they realized their special situation.

"Donnie! Donnie, get back here now!" Leo cried out to the massive turtle who was just ignoring him on purpose. Raphael snickered while Mikey looked a little horrified. Donatello was in the middle of a dirt pile sitting quietly with the occasional sneeze whenever dirt invaded his sensitive nostrils. It looked like the massive mutant turtle was enjoying himself in the soft pile of hard mud and dirt. His body was covered in it. Leo cringed.

"What if he catches something!" Mikey shouted, "Donnie, c'mere boy-" he whistled to catch the mutant terrapin's attention which seemed to work. Instead of listening Donatello roared, a clear sign to leave him in peace. Leo wasn't having none of his attitude today. Leo stomped towards the creature, walking tall to show that he was in charge and that the creature should recognize it. Donatello glared at his older brother his attention directed over to him with curiosity of what the leader planned to do. Raphael couldn't help but wish for a showdown. His fearless leader needed a good butt kickin'.

"Donatello, we're going home now," Leo said firmly, "Get out from th-Ahhh!"

Donatello had gotten up at lighting speed to grab Leo by his shell. His entire hand had engulf his carapace but he didn't seem interested in crushing his brother. Leo's arm and legs flailed in a mini panic from being carried like a common item to the mutant turtle. He could hear his other brother's scream in laughter and point at his distress.

"A little help!" Leo snapped angrily to his siblings. Donatello growled at the older terrapin making him Leo flinch and stare nervously at his once gentle and calm brother. "Donnie, let me down!" Leo demanded.

Donatello stared dead into his brother's eyes and puffed out a hot exhale into his face. Leo sighed, he didn't know what that was suppose to mean but seeing as he wasn't on the ground right now...

"Donnie, let him go please! C'mon, bro leave stinky turtle alone," Mikey attempted with a large grin. Donatello turned his eyes to the younger turtle much to Leo's horror. At first Leonardo though Donatello was about to attack his brother when suddenly he was dropped like a forgotten toy. Leo landed on his shell with loud _thud. _He groaned from the painful impact. There was no way that Mikey won his brother over so easily just with an added 'please'. Leo gritted his teeth together and glared up Donatello who now had his attention on the youngest turtle.

Mikey opened his arms up as if he was attempting to hug the giant turtle, "Donnnnn, let's go to the lake! I bet you'd like the lake-"

"Lake sounds nice right now," Raphael uttered.

Leo snorted, "No, we're going home."

"But but-" Mikey began but Raphael quickly interrupted.

"Think about it, Leo, Master Splinter is going to throw a fit if we bring Donnie back all dirty."

Leo opened his mouth to argue but nothing came out. He really didn't want to go for the free of being found. The sun was going down but he still didn't want to take the chance. His brother stuck out more than they did. Leo sighed, "Fine but we'll be quick about it."

The trip to the lake was short thankfully. They had chosen the one closet to their home near the dense forest where Leo hoped no humans would venture. They did a quick check around the area before giving the okay.

"Donnie! Come on, dude!" Mikey pushed at his brother's massive shell with all his might but couldn't move Donatello. The massive turtle just sat with his legs spread out and sniffing the area curiously. Raphael had jumped into the water to try and coax their brother to follow. However, Donatello didn't seem interested in the water. Leo crossed his arms, impatient and annoyed that they had wasted time trying to lure the creature to the water. Donatello looked up to see Raphael sitting with his shell facing him in the swallow end of the lake. Something seemed to click in the massive turtle's brain and he slowly stood on his two feet.

"Yeah!" Mikey encouraged his brother.

Leo watched as Donatello stomped his way over to the lake straight towards Raphael. Raph turned his head towards the heavy footsteps and was surprised to see his sibling towering over him.

"Christ, Don.." Raphael still wasn't use to his brother being so...well big and intimating. Raph would be lying if he said he wasn't a tad bit nervous around the giant turtle. Unlike Leo though, he still saw his gentle brother within. Raphael went to go stand on his feet when suddenly Donatello grabbed him. He wrapped his massive arms around his brother and lifted him out from the water.

"Don!" Leo shouted. He raced over to help his brother when he saw the massive turtle sit down in the water with a splash. Raphael was frozen in his brother's embrace. Donatello didn't know his own strength and could have easily broken Raphael's spine into fourteen pieces. However, Don was gentle and didn't apply as much pressure in his hold. He relaxed a little and his caution was replaced with confusion.

Mikey hopped into the water besides them, "Easy Donnie!"

Donatello ignored the young turtle. His tail was submerged in the cool water, happily swaying it from side to side and lifted it to create a splash. He was enjoying the water. Raphael squirmed a little in Donnie's hold but every time he got an arm free, Donatello would grab it again and bring it back into his iron hold.

"Ugh."

Leo wasn't so carefree about Don holding his brother like that. He was hovering around them just in case his brother decided to break Raphael like a KitKat bar.

Suddenly, Raphael cried out in horror.

Leo was had dashed as fast as he could towards the two, ready to fight his brother-

What he saw made him freeze in his tracks.

Mikey was crying with laughter, smacking his hand over his eyes and fell backwards onto his shell. Raphael was cringing as he felt his brother's large tongue sweep up his neck and over his bald head. It must have been the oddest sensation Raphael ever felt in his life. His tongue reminded him of sandpaper. A wet strip of sandpaper gliding over his skin and making him shiver.

"Hahaha! Oh my god!" Mikey chuckled at the sight of Donatello attempting to clean his brother. Leo couldn't stop the corners of his mouth twitching upward at the sight. Raphael looked mortified as he stared up at the oldest with pleading eyes to help him out.

"D-Donnie! Cut that out!" Raphael barked angrily at his massive sibling. He couldn't get his arms feet so he tried to scare his brother away with big splashes he made with his legs. Donatello wasn't amused and merely purred at the cool water.

"I think he's trying to tell you you need a bath more that he does," Leo said as he snickered. Raphael glared at him and growled.

"Don! You let me go or I'm gonna-" Mikey's laughter drowned out his threat and he slumped over in defeat.

"If April and Casey hear about this I'll ringing all your necks..."


	3. Chapter 3

The first time Don had hurt Mikey was when they were alone together. Mikey knew it was an accident and Don looked apologetic even. Okay, maybe he was stretching it a bit. Donatello was angry, beyond angry. It had to have been the narrow tunnels making him feel caged in and anxious. Mikey wasn't really sure and he couldn't blame the guy. Mikey was guided his brother through the passage ways, happily skipping and beckoning for his brother to follow. The next he found himself flying through the air and hitting his shell against the hard concrete.

"Don!" Mikey cried out and screamed when he saw his large sibling charge straight for him. He leapt up just time before Don collided with him and rolled towards a safe distance. Donatello hit his head against the brick and howled loudly in pain.

"Take it easy, bro," Mikey coaxed but Don was deaf to his brother's voice. Don roared angrily into the brick and slammed his large fist into the wall, smashing it instantly like it was made out of play doh.

"Eeep!" Mikey quickly got to his feet but remained still from his distance. He didn't know why Don was acting like this and it scared him. His brother was easily stronger and bigger than him and could break him like a toothpick. Donatello snapped his head towards the frighten turtle, smelling the fear and dread from his brother. Mikey ducked his head a little with his hands out stretched towards him.

"Don! What's wrong? Come on don't scare me like this," he rambled. Donatello ran straight for him again and swiped his enormous claw straight at the orange clad turtle. Mikey dodged the attack but felt Donatello's sharp nail graze his leg painfully. Mikey crashed into the opposite wall and clutched his bleeding calf.

"Oww!" Mikey whined. The cut was deep and blood pooled out between his fingers onto the ground. Donatello turned to face his brother again but this time he was still. Mikey felt his blood run cold inside him as he stared back at his sibling wondering what was going inside that big head of his. Donatello sniffed the air and caught the scent of blood through his sensitive nose.

"D-Donnie?"

Donatello made a low moan through his closed jaws like a sympathetic purr as he stared at his younger brother. Mikey could say that he was relaxed at all.

After a few minutes of just staring Don had walked over to his brother laid on his belly in front of Mikey. Mikey smiled at his brother. Don's face was neutral but his emotions were read through his body. He wished his brother could talk to him again he wanted to hear those intelligent and complicated words from Donatello. His brother was a good listener as well as a good advice giver. Mikey never thought he would actually miss his brainy brother speak about..well science junk. As far as Mikey knew, Donatello hadn't uttered a word ever since his second mutation. He responded in grunts, growls, and body language. Mikey took the time to analyze his sibling for the seer purpose and obvious answer for communication. He felt like an idiot when he didn't notice the distress signs from Donatello when they entered the narrow corridors of the sewers. Don really hated being boxed in and it was for a good reason.

Mikey could still feel the blood running down his leg, collecting underneath him in a large puddle and he felt light headed.

"D-Donnie..I need a ride, buddy," Mikey chuckled lightly as he reached out his free arm towards his brother. Donatello stared his brother for a few seconds before complying. Donatello crawled closer to his brother so that Mikey could grab his shoulder and hoist himself up. He wobbled at first but thankfully he had Don's support. Mikey clung to Don's back like a life line and at first he was afraid that Don was uncomfortable with his position and would throw him off. Don was still lowered as if contemplating whether or not he liked Mikey on his back.

"Don, come on," Mikey said softly. He didn't want to scare his brother or make him upset again. Donatello surprisingly obeyed walked on all fours back to their lair. Mikey could still feel his brother's nervousness about the walls that surrounded them so closely. Donatello would growl and bite at the narrowing passage and broke into a run just to escape them and relaxed once they reached the more open routes.

Mikey knew he must have passed out because he the next thing he knew he was laying comfortably on the main room sofa. His head was throbbing and his leg burned with pain still. It took him a while to figure out that he was safe in the lair all thanks to brother. Mikey lifted himself off from the sofa carefully, holding his head as he felt a sudden dizzy spell.

"Mikey, you're awake,"

Raphael was at his side in an instant and gently lowered his brother back on to the sofa, "Just lay back down, shell brain, you lost a lot of blood there."

Mikey groaned, "W-where's Donnie?"

"Sleeping right next to ya'" Raphael answered. Mikey opened his eyes to see his brother point besides the sofa to where Donatello was laying silently. His massive form couldn't be missed and all Mikey had to do was turn his head a little to see his brother's large and abnormal shell.

"What happened out there?" Raphael asked with concern.

Mikey hesitated. He knew he shouldn't tell his brother that Donatello attacked him. They wouldn't understand, none of them would and he didn't want them overreacting. Don was scared and what do scared animals do? They lash out in fear. He wouldn't dare tell Leonardo cause he would he would freak out the most. The prolonged pause from Mikey made Raphael grow impatient and he roughly jabbed his finger into Mikey's side.

Mikey yelped, "Hey!"

"What the shell happened out there?" Raphael asked again.

"I fell okay? I was messing around like I always do when I tripped and fell into some junk," Mikey answered rudely.

Raphael crossed his arms in disbelief.

"It's the truth! And if Don wasn't there it could have been worse!"

Raphael upped the corner of his mouth upward, pressing his lips together at his brother's explanation and shook his head. "You went to the old tunnels did ya? You know we're not suppose to go that far."

Mikey felt a rush of relief wash over him, "Y-yeah I know..sorry.."

Raphael gave his brother a smack on the shoulder before leaving the injured turtle to rest. Mikey sighed, turning his head to the side so that he could catch a glimpse of his sleeping brother.

"You owe me big time, bro," Mikey said with a smile.


	4. Chapter 4

_A/N: _I wanna thank my awesome friend for the cover image for this story! Look it's Leo and Donnie! It's cute. Please visit her tumblr: neosmies.

It felt different not having their genius brother around with them. Donatello's presence was skim at best considering he liked to be locked in his own little world with his inventions. Raph actually admitted to missing the nerd turtle's rants and science ramble.

He didn't exactly want to call his brother stupid right now. Somewhere inside that big hunk of shell was their genius brother. It was hard to see it though sometimes when _this _Donatello didn't the know the difference between his punching bag and actual food.

"Damn it, Donnie!" Raphael bellowed in anger. The massive turtle was lying down, curled up with its massive arm around his beloved punching bag. He had his large teeth already stabbing into the bag, chewing it like a dog would his favorite bone. Raphael felt his blood boil in pure rage. Donatello didn't move his jaws away from the bag, instead he looked up towards his brother with a glare. Raphael wasn't the least fazed by it. He wanted his punching bag!

"Don, let go! Now!" Raphael barked loudly at the turtle. Donatello continued to glare at him and even growled back at his hot headed brother. He dared the smaller turtle to take his toy away. Raphael stomped closer to Don, his fists clenched and teeth baring. Donatelo immediately took in the threat and raised his head towards him. Raphael stopped, "Listen here-" he pointed an accusing finger towards his mutated sibling, "You can go chew on Mikey's leg for all I care just not my bag! I already told all of you to keep away from my bag!"

Donatello just swayed his tail from side to side with a stoic face. Raphael waited for the other to response but fully knew that the other couldn't speak. Don sat on his bottom in front of his brother and then grabbed hold of Raphael's bag and placed it back into his mouth. Donatello stared back at the tiny turtle, daring him to go ahead and try to take it away from him. Raphael let out a frustrated cry and grabbed his head to avoid punching his brother into mash.

"What's going on here?"

Leonardo appeared into the main room with a pack of crackers in his hand. Raphael turned towards the oldest, his last hope.

"Leo! You gotta do something," Raphael growled as he motion his hands dramatically towards Donatello. Don was sitting quietly with his bag in his mouth, looking between Leo and Raph now. Leo looked up at Donatello and chuckled. Raphael quirked a brow, "You think that's funny?"

"I do," Leo replied simply, "You know you aren't going to get that back now right?"

Raphael stared in annoyance then growled. "Don put it down!" Raphael shouted at Donatello once more.

Donatello continued to just stare at his siblings with a neutral expression. Suddenly, Donatello got on all fours and began to shake his head vicious with the punching bag still in his hold. The threading was instantly torn apart from the force and the sand within fell down beneath him. Raphael watched in horror as Donatello destroyed his beloved punching bag. Leo couldn't help but laugh at this and quickly covered his mouth to muffle his snicker.

Raphael stomped away angrily, cursing under his breath and turning bright red from heated rage. Donatello bit and chewed at the now fully destroyed equipment then dropped it with a content snort. Donatello watched Leo as his eldest brother strolled away from him, the crackers still in hand and his sudden interest spiked.

He hurried towards the blue clad turtle, jumping over him then landing in front of Leo with a earth shattered 'thud'. Leo nearly lost his footing, holding the cracker in both hands and stared down his brother. Donatello was on all fours again but he still managed to tower over even the oldest. His tail moved from side to side watching his brother for his next move. Leo shuffled to the right, Don followed. Leo shuffled to the left and again Don followed.

"Uh.." Leo began looking at the massive turtle with confusion, "Do you..want something Don?" It was still hard for him to actually call this beast his brother. Donatello lifted his large snout towards Leo and carefully nudged his brother on the shoulder. He let out a loud exhale before crawling towards to his brother. Leo was beyond confused of his brother's display.

"Are you hungry?" Leo asked his brother. It felt degrading to ask his brother such a simple question. However, he was reminded that Don had no means of communicating with them despite body language and unintelligent noises. As guessed, Donatello made a small grunt. He opened his mouth partially then aimed for the crackers in his hand. Leo moved back a little thinking that the other was going to bite him but realized it was just the crackers the turtle wanted.

Leo chuckled nervously, "Oh.." He piped as he grabbed a few crackers then held his hand out to Donatello. Don sniffed the food first before licking Leo's hand. Leo cringed but still held his hand out, Don's tongue felt like sandpaper. He licked up the crackers and ate them noisily with gusto. Leo reached back into the bag and pulled out several more but instead he waited for Don to finish before presenting.

Donatello moved a little closer to Leo when suddenly-

"Arrrghh!"

Leo tried to pry Don's mouth open with his free hand while the other was tightly clenched in Don's jaw. Thankfully, Donatello didn't apply as much pressure to actually harm him but it was still alarming. Leo was surprised to know that Don had the jaw of a snapping turtle. He didn't even flinch.

"Don! Let go now!" Leo bellowed frantically. He didn't know if Don understood what he was actually doing. He feared that his brother would surely take his hand clean off. "Donatello!" Leo tried again and he was trying not to panic.

Out of no where Mikey had appeared to his left. He casually strolled over between the two, looking as if he had just woken up from a deep sleep then stopped in the middle. He looked at the situation, uninterested, before suddenly lifting his hand up to Don's large snout and flicked his finger firmly right on the nose. Donatello let out a small howl and released Leo's hand.

"Bad Don! Leo's hand is not food!" Mikey said firmly as if he was scolding a child. Donatello backed away but not without a growl towards the oldest. Mikey glared back at the large turtle with his hands on his hips but relaxed once Donatello had lost interest in both of the turtles.

Leo blinked. "H-how did you-"

"He doesn't like it when you hurt his nose," Mikey answered then yawned, "I guess it makes him submissive or something I dunno. Can you keep it down though I'm trying to sleep?" Mikey gave his brother a small pat on the shoulder before leaving Leo still confused over what had just happened.


End file.
